Hypodermic syringe tip assembly



Oct. 29, 1957' w. G. DUNNICAN ,8

HYPODERMIC SYRINGE TIP ASSEMBLY Filed Sept. 13, 1955 2 Sheets-Sheet. 1

' INVENTOR Ward gz' flumm'au/ fimm ATTORNEYS Oct. 29, 1957 w. G. DUNNlCAN HYPODERMIC SYRINGE TIP ASSEMBLY 2 Sheets-Sheet 2 Filed Sept. 13. 1955 INVENTOR I'd 21rd f1 flan/army ATTORNEYS BY km. BM Mm.

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United States Patent HYPODERMIC SYRINGE TIP ASSEMBLY Ward Dunnican, Clifton, N. J., assignor to Becton,

Dickinson and Company, Rutherford, N. 1., a corporation of New Jersey Application September 13, 1955, Serial No. 534,062

17 Claims. (Cl. 128--218) This invention relates to a structurally and functionally improved hypodermic syringe and especially the tip assembly thereof.

By means of the present teachings, a structure is furnished which will, in effect, be free from all cavities and recesses within which medicament may lodge. Accordingly, the syringe may be cleared and the danger of nonsterility as well as a subsequent medicament intermingling with the residue of a previously injected medicament is overcome. It follows that undesirable discoloration of syringe surfaces is avoided under the heat of autoclaving incident to the elimination of such residues.

Another object is that of furnishing an assembly which will be free from leakage and in which, when the several parts are properly grouped together, they will remain in efficient and proper relationships throughout the entire life of the syringe and despite the fact that the latter may have its surfaces repeatedly subjected to cleaning operations involving detergents, be exposed to sterilizing actions and also to medicaments of diverse types.

An additional object is that of designing an assembly which will include relatively few parts, each individually simple and rugged in construction, and capable of manufacture by quantity-production techniques. Accordingly, the cost of providing the desired structure will be minimized.

With these and other objects in mind, reference is bad to the attached sheet of drawings illustrating practical embodiments of the invention, and in which:

Fig. 1 is an exploded view of the several components utilized;

Fig. 2 is a transverse view taken along the line 2-2 in the direction of the arrows as indicated in Fig. 1 and with a part of the washer broken away to disclose underlying construction;

Fig. 3 is a sectional side view of the parts prior to their final assembly;

Fig. 4 is a similar view of such final assembly; and

Figs. 5 to 11 inclusive are fragmentary sectional views of the outer end portions of syringe barrels and each showing alternative structures to those illustrated in Figs. 1 to 4.

In these views, the numeral 5 indicates the body of the syringe barrel which is formed of glass. In accordance with conventional practice, this barrel presents an open inner end usually defined by an integral flange. This end portion has not been shown in that it forms no part of the present invention. Likewise the plunger or piston of the syringe has not been illustrated. Suffice it to say that as this piston is reciprocated within the bore of the barrel, medicament is drawn into or expelled from the latter. That medicament flows through the bore of a tip 6 which is integral with the outer end of the barrel and serves as a mounting for a fitting by means of which a hypodermic needle may be coupled with the barrel.

The fitting includes a cup-shaped body embracing side walls 7 and a base 8. Extending outwardly from the latter is a collar 9, the inner face of which presents a thread 10. This collar is concentrically disposed around and spaced from a tip or nozzle portion 11 integral with the remaining parts of the fitting. In accordance with conventional construction, the outer face of this nozzle is preferably tapered. As is well understood by those conversant with this art, the hub of a needle (not shown) is ensleeved over the nozzle or tip portion 11. Thereupon, by rotating that hub with respect to the fitting, extended portions of the former engage with thread 10. Under continued rotation, the needle hub is drawn into the space between the nozzle and collar 9. As it is so moved, the bore of its hub is sealingly engaged by the outer surfaces of the tip 11. At the same time, the needle becomes a fixed part of the syringe barrel. A relative movement of the needle and its hub in a reverse direction with respect to the fitting results in a release of the needle.

The space defined by the side walls 7 of the fitting is such that tip 6 may be accommodated therein. To secure the parts against displacement, a force fit is preferably resorted to. It is obvious that in accordance with well known designas shown in my earlier U. S. Patent No. 2,711,171 of June 21, 1955the side walls of the cup may be secured against detachment from the tip portion 6 by having these parts formed with cooperating screw threads. Otherwise, the edge portion of the side walls 7 may be spun inwardly to engage against the base surfaces of the tip. In the present exemplification, a force fit has been shown for illustrative purposes.

As in Figs. 1 to 4 inclusive, the nozzle or tip 11 is provided-with an axially extending bore 12. This tip may be slightly tapered to provide a surface properly cooperative with the hub of a needle (not shown). The bore is continued beyond the base 8 in the form of an annular flange 13. Adjacent the outer face of the latter, the base may be provided with an annular recess 14, the outer side edges of which are tapered or inclined as shown. A washer 15 is interposed between the adjacent outer face of tip 6 and the inner face of base 8. This washer is provided with an opening 16 which may have a diameter less than that of the tip bore. At this time, it is to be noted that the tip 6 preferably has inclined surfaces 17 defining its outer edge zone.

The effective height of flange 13, i. e., the distance to which it extends beyond the inner surface of base 8, should be substantially equal to the thickness of washer 15. The diameter of the opening or aperture 16 of the washer should be in excess of the external initial diameter of the flange 13. The external diameter of this washer should be substantially equal to the internal diameter defined by the annular walls 7. Thus, as shown in Figs. 1 and 3, this washer will have its outer edge zone extending beyond the inclined or beveled face 17 of tip 6. The outer face of that tip adjacent the outlet of its bore should terminate in substantially right-angularly extending surfaces. The bore diameter thus defined will be less than the diameter incorporated in flange 13.

The material providing the washer 15 should embrace a non-toxic elastomeric compound. Specifically silicone is employed. This will include a combination of organic and inorganic substances, the organic part consisting of one or more hydrocarbons with the inorganic part embracing silicon. The compound is identified generally under the term of silicone rubber. This will have the property of being inert to virtually every type of medic..- ment. Also it will spread under pressure and be readily resistant to temperature extremes such as are encountered under dry heat or 'autoclaving sterilization and room temperatures. This material will also maintain its resiliency. Additionally, it will not tend to adhere to either the surface of the glass tip nor the metal of the fitting.

As indicated in Fig. 1 and shown in Fig. 3, the washer may be disposed upon the outer surface of tip 6 or adjacent the inner face of base 8. Thereupon, the side wall 7 of the cup structure is ensleeved around tip 6 so that the parts assume the position shown in Fig. 3. Now as further pressure is applied to dispose the cup in telescopic relationship with respect to the tip of the barrel, the condition illustrated in Fig. 4 is brought into being. Under the circumstances shown in the latter figure, the fitting is completely mounted on the syringe barrel.

As will be understood with the application of pressure beyond that necessary to establish the relationship shown in Fig. 3, the flange 13 rides against the outer surface of tip 6. The flange being relatively thin and the metal of the fitting being of proper character, that flange functions as a seal-providing element in that it distorts in the direction of the outer surfaces of recess 14 as the parts are increasingly telescoped with respect to each other. Washer 15 in its initial and uncompressed state, having a diameter substantially equal to that of the cup portion of the fitting, it follows that its diameter cannot increase under conditions of pressure. Its aperture or opening 16 will, under these conditions, of course contract in diameter to snugly embrace the flange 13. That flange bulging outwardly will even further confine the space available for the accommodation of the gasket 15. Therefore, the material of the gasket will be displaced or caused to flow into the recess 14 to substantially fill the latter as shown in Fig. 4. It will also be caused to flow into the space initially existing between the surface 17 of tip 6 and the adjacent inner surfaces of the cup portion of the fitting. Under these circumstances and as also shown in the latter figure, this space will be substantially filled with gasket material. The inner face of flange 13 will furnish a bridging portion or conduit intervening the bore 12 of tip or nozzle 11 and the bore of tip 6. Wherever the edge of flange 13 does not directly engage the outer face of tip 6 in fluid-tight relationship, gasket material will crowd into any spaces existing so that the continuity of the bore will not be interrupted.

Under those conditions, no cavities will be present within which medicament may lodge. Difliculties inherent to such a structure are therefore overcome. Despite the extremes of temperature and the differential of expansion and contraction existing between the barrel tip and the fitting under those extremes, the seal will not be detrimentally aflected. Merely the material of the seal will flow under the dilferent pressure conditions which follow as a result of the temperature variations. An extremely stable form of mounting is achieved for the fitting. When once established, and regardless of whether a force-fit, peening, screw-threading or any other form of coupling is used, the stability of the parts will be maintained.

The same displacement or flow effect may, of course, be achieved by different structures which serve to exert pressure on the washer or packing element so as to displace the material to substantially completely fill all voids. In Figs. to 11 inclusive, and in common with Figs. l to 4, the outer face of tip 6 is beveled'as at 17. Such beveling need not, in all instances, be resorted to. However, it has been found generally to be a desirable factor. As in Fig. 5, a flange of lip portion 18 is provided on the inner face of base 8 and defines a bore which is a continuation of the bore 12 of tip 11. A washer 19 having the characteristics of washer is interposed between the adjacent faces of the tip and the base 8. The thickness of this washer should be substantially greater than the height of flange 18 when that washer is not subject to compression. Likewise, the opening of the washer or packing element should be of a diameter in excess of the external diameter of lip 13. Therefore, as the side wall 7 of the fitting is ensleeved over tip 6, the washer will be subjected to compression. This will cause the material of that element to flow to substantially fill the space between the tapered face 17 and the inner face of collar 7. Also the washer will constrict around flange 18 to have its edge firmly engaging the outer faceof that lip. Therefore, when the fitting has once reached fully seated position, at which the edge of flange 18 will engage the surface of tip 6, all intervening spaces will be tilled by the washer.

In :Fig. 6 and subsequent views, the washer has again been identified by the numeral 19. That washer should preferably comprise simply a perforated disc of gasket material preferably of the type afore described. Of course, it may be generally shaped to conform to the space within which it is to be accommodated. This has generally been found to be unnecessary however. The desired flow effect to fill all voids is achieved in the structure illustrated in Fig. 6 by providing a flange 20 extending inwardly from the base 8 of the fitting and which flange has an inclined outer face. The tip 6 has the outer end of its bore surface modified as at 21 to furnish a similarly sloped area. Therefore, as pressure is exerted upon washer 19, incident to forcing the fitting upon tip 6, the material of the washer will not alone flow into the space existing between the inner surface of collar 7 and the adjacent face 17 of the tip, but will also move into the gap existing between the outer face of flange 20 and the beveled surface 21 of the tip. This movement of the packing or washer element will continue until its aperture in effect provides a bore portion aligned with and of substantially the same diameter as the bore 12 of tip 11 and the bore of tip 6. Again, no voids will exist and a stable mounting result.

By reversing this structure, the same results are achieved. In other words, as in Fig. 7, the base portion of nozzle 11 adjacent its bore surface may be beveled as at 22. The material of tip 6 may be surfaced to furnish a truncated cone portion 23 defining its bore. The angularity of surface 23 may be slightly greater than that of surface 22. With the washer interposed between the tip and base surface 8 and if the former be provided with a beveled face 17, the outer edge zone of the washer will flow or be displaced in. the manner heretofore described. In addition, the material of the washer adjacent its central perforation will be pinched between the converging surfaces 22 and 23. Therefore, it will be displaced inwardly as indicated at 24. Accordingly as the fitting reaches a properly ensleeved position over tip 6, the gasket will define a bore which, in eflfect, is of the same diameter and contiguous with the bores of the nozzle 11 and tip 6.

As in the case of the structure shown in Fig. 8, a flange or head 25 may extend from the base of the fitting toward the tip 6 and have a height substantially equal to the thickness of the washer when the latter is uncompressed. The bore of tip 6 is flared or beveled in an outward direction as indicated at 26 and in a manner similar to that shown in Fig. 6. As the fitting reaches its fully seated position, the washer will be subjected to pressure. Therefore, it will bear against the outer face of flange or bead 25. It will enter the space existing between the latter and the beleved surface 26 and will completely fill all voids.

In Fig. 9, the outer face of tip 6 is in all respects similar to the showing of this part in Figs. 1 to 4 inclusive. However, the lower face of base 8 is divided into two surfaces, one of which extends at an obtuse angle and another at an acute angle with respect to the axis of the assembly. The point of juncture of these surfaces has been indicated at 27. In common with the previously described forms, a cam structure is furnished which acts on the gasket as the fitting is shifted to fully seated position. So acting, it exerts pressure. Therefore, the gasket material flows not alone outwardly to fill substantially all spaces between the base 8 and the tip 6 adjacent the outer ends or sides of the latter, but also shifts inwardly to define a bore which is contiguous with the bores of nozzle 11 and tip 6.

Referring to Fig. 10, the inner surface of base 8 may be inclined upwardly in a radial direction as indicated at 28. Therefore, that portion of this base which is adjacent the bore of nozzle 11 will be in immediate proximity to the surface of tip 6 when the fitting is fully seated. Under these circumstances, a minute amount of washer material may intervene tip 6 and base 9 adjacent the bore portions of the same. Such disposition of the parts Will, of course, occur as the fitting reaches a fully seated position.

It will be appreciated that it is ordinarily too expensive to form actuating ribs, beads or flanges in the material of the glass tip 6. Therefore, a preferred exemplification of forming these parts in the fitting has been resorted to only in Fig. 11. In that view, a flange or lip 29 is formed in the surface of base 8 immediately adjacent the bore 12 of nozzle 11. That flange preferably has both of its faces sloping so that, in section, a triangular configuration is presented. Concentrically disposed with respect to flange or lip 29 is a similar ridge 30. Both of these parts will act as cams in conjunction with the material of the washer or packing element as the fitting assumes its fully seated position. Therefore, this washer will have its aperture or perforation constricted so as to extend in line with the nozzle bore. It follows that no voids will remain.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. It is obvious that numerous changes in construction and rearrangements of the parts might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

1. In combination a glass syringe barrel, a bored tip at one end of the same, said tip presenting a beveled surface adjacent its outer surface, a fitting, a bored base forming a part of said fitting, said fitting being ensleeved over said tip to retain said base in a position adjacent the outer tip surface with the bores of said tip and base in substantial alignment, an initially substantially flat washer of displaceable material interposed between the adjacent tip and the base surfaces, said washer being subjected to compression incident to such surfaces being moved towards each other to cause said washer to substantially completely fill the space between the base and tip and also move into engagement with such beveled surface and means for preventing such washer from spreading into the space defined by the aligned bores of said base and tip.

2. In combination a glass syringe barrel, a bored tip at one end of the same, said tip presenting a beveled surface adjacent its outer surface, a fitting, a bored base forming a part of said fitting, said fitting being ensleeved over said tip to retain said base in a position adjacent the outer tip surface with the bores of said tip and base in substantial alignment, an initially substantially flat washer of displaceable material interposed between the adjacent tip and the base surfaces, said washer being subjected to compression incident to such surfaces being moved towards each other to cause said washer to substantially completely fill the space between the base and tip and also move into engagement with such beveled surface, means for preventing such washer from spreading into the space defined by the aligned bores of said base and tip and means forming a part of said fitting and distortable as the latter is ensleeved over said tip to engage with the adjacent surface of the washer and shift the material of the latter away from the space defined by the aligned bores.

3. In combination a glass syringe barrel, a bored tip at one end of the same, a fitting, a bored base forming a part of said fitting, said fitting being ensleeved over said tip to retain said base in a position adjacent the outer tip surface with the bores of said tip and base in substantial alignment, a washer of fiowable material interposed under compression between the adjacent tip and base surfaces and the aperture of said washer being constrictable in diameter under such compression whereby the edge of said aperture tends to move into the space defined by said aligned bores and a distortable seal-providing element encircled by said washer. Y

4. In a syringe combination as set forth in claim 3, said element comprising a flange forming a part of said fitting and being encircled by said washer and said flange being deformable by engagement with said tip as the base of said fitting moves towards the body of said barrel.

5. In a combination as set forth in claim 4, and said base adjacent said flange being formed with a washerreceiving recess.

6. In combination, a bored syringe barrel tip member, a fitting member comprising an apertured base disposed adjacent the outer tip face and a collar ensleeved over said tip, a perforated washer of flowable material interposed between the tip and base and means forming a part of one of said members and extending into engagement with the surface defining the perforation of said washer to cam against the latter and displace portions of the washer body to substantially fill all voids between said base and tip.

7. In the combination as specified in claim 6, the perforation of said washer being initially of a diameter greater than the diameter of said tip bore and aperture of said base, and said cam means also contracting such washer perforation.

8. In the combination as specified in claim 7, at least certain of the surfaces of said cam means being incorporated in said fitting member.

9. In a combination as specified in claim 7, at least certain of the cam surfaces being incorporated in said tip member.

10. In combination a glass syringe barrel, a bored tip at one end of the same, a fitting, a bored base forming a part of said fitting, said fitting being ensleeved over said tip to retain said base in a position adjacent the outer tip surface with the bores of the tip and base in substantial alignment, an apertured washer of flowable material interposed under compression between the adjacent tip and base surfaces, the aperture of said washer being constrictable in diameter under such compression whereby the edge of said aperture tends to move into the space defined by said aligned bores, and a bored seal-providing element extending from the base of said fitting and contactible with said tip to distort and expand said element to displace the edges of the washer aperture adjacent thereto.

-11. In combination a glass syringe barrel, a bored tip at one end of the same, a fitting, a bored base forming a part of said fitting, said fitting being ensleeved over said tip to retain said base in a position adjacent the outer tip surface with the bores of the tip and base in substantial alignment, an apertured washer of flowable material interposed under compression between the adjacent tip and base surfaces, the aperture of said washer being constrictable in diameter under such compression whereby the edge of said aperture tends to move into the space defined by said aligned bores, a flange forming a part of said fitting and being encircled and initially engaged by said washer and said flange being deformable by contact with said tip as the base of said fitting moves towards the body of said barrel.

-12. In a syringe combination as set forth in claim 11, and said base adjacent said flange being formed with a washer-receiving recess.

13. An assembly of the type described including in combination a syringe barrel, a tip at one end of the same and formed with a bore affording communication with the barrel interior, a needle-mounting fitting comprising a cup-shaped body ensleeved over said tip, the base of said fitting being formed with an opening, an annular flange extending upwardly from the base of said fitting in line with said opening, said flange and the bore of the tip presenting surfaces substantially aligned with each other, an apertured washer of displaceable material interposed between the base of said fitting and the end of said tip and at least one of said surfaces including a camming face functioning as said cup-shaped fitting is telescoped over said tip to "bear against the edge defining the aperture of the washer to displace material of the latter outwardly and establish a leak-proof passagefree from interruption-from the base of said cup to the interior of the barrel.

'14. In an assembly of the type described in claim 13, said annular flange being outwardly expandable to provide such camming face as the free edge of saidflange is subjected to forcible end thrust and distortion incident to opposing the tip end as said fitting is telescoped over said tip.

'15. In an assembly of the type defined in claim 14, and said base being formed with an annular recess extending around said flange, said recess receiving material of said Washer displaced by such camming action.

16. In an assembly of the type defined in claim 13, the aperture of the washerin its initial state-having a diameter greater than that of the annular flange and said washer bearing in intimate contact with the opposed faces of said base and tip.

17. An assembly of the type described including in combination a syringe barrel, a tip at one end of the same and formed with a bore afiording communication with the barrel interior, a needle-mounting fitting comprising a cup-shaped body ensleeved over said tip, the base of said fitting being formed with an opening, an annular flange extending upwardly from the base of said fitting defining a continuation of said opening, the bores of said flange and tip being substantially aligned with each other, an apertured was-her of displaceable material interposed between the base of said fitting and the end of said tip and encircling said flange, the base of said fitting presenting in its surface a circular groove and part of said washer being received by said groove.

References Cited in the file of this patent UNITED STATES PATENTS 1,471,644 Bandman Oct. 23, 1923 2,432,605 'Baraeh Dec. 16, 1947 2,656,836 Hickey Oct. 27, 1953 2,711,171 Dunnican June 21, 1955 OTHER REFERENCES Servais: New Developments in Silastic, India Rubber World, August 1946, pages 657-659 and 662. (Available in Scientific Library.) 

